Metallic Particle Suppression in ±550 kV GIS: A Study on Trap Parameter Optimization

Metallic particles are inevitably generated in DC gas-insulated switchgear (GIS) due to handling, friction, and other factors. In this paper, based on a ±550 kV GIS particle experimental platform, the motion characteristics of particles are investigated. The effects of particle traps with different baffle angles, different porosities, and the application of films under the traps for particle suppression are discussed. The results indicate that, in the absence of particle traps in GIS, there is a possibility for millimeter-sized bulk metallic particles to strike the spacer and accumulate in regions of low electric field intensity. The movement of 3 g of metallic particles inside the GIS can cause the device leakage current to rise sharply, reaching 4.5 to 6 times the average value during that period. Adjusting the baffle angle of the particle trap according to the motion characteristics of metallic particles can improve the particle capture performance, with the optimal baffle angle in GIS ranging between 180 and 270 degrees. When the velocity of metallic particles decreases and the collision reflection angle is reduced, reducing the pore size of the particle trap can still ensure that the particles successfully enter the trap, while the relatively increased size of the metal mesh enhances the probability of particles being blocked within the trap area. Applying a film beneath the trap can further improve the capture effectiveness, increasing the length of the trap in front of the spacer with no particle intrusion by 61.66%. The conclusions of this paper provide guidance for the design of metallic particle suppression techniques in DC GIS and for the development of stable and reliable DC gas-insulated equipment.